Evolving electronic components are operating at higher speeds and higher power levels and are being packed more and more densely. As a consequence, these components are generating increasingly larger amounts of heat in smaller areas. To limit the temperatures of these components, and thereby realize peak performance plus reliable operation, this heat energy must be effectively removed.
The continued trend in digital electronic integrated circuits, such as computer processors, is to form more active devices (transistors) into smaller areas and to operate these devices at higher speeds. The by-product of this trend is the generation of very high heat densities. Removal of this heat has been identified as perhaps the biggest issue facing computer designers. Consequently, to support performance improvements, effective heat extraction techniques are essential. New transistor materials, such as silicon carbide, are being developed for both analog power and radio frequency (RF) devices. These materials enable generation, conversion, and management of much higher power levels than has been previously possible. Heat densities at the point of generation can be on the order of 7000 Watts per square millimeter peak, ten times the amount associated with current transistors. To fully realize the potential of these new material components, effective heat removal techniques are needed.
Opto-electronic components, such as laser diodes and photo-detectors, must be maintained within temperature bounds to operate properly. As their power levels increase, techniques for removal of their excess heat, so as to maintain preferred operational temperatures, are essential.
Next generation radar systems will be required to deliver high levels of performance and operational flexibility, feature exceptional reliability, and be amenable to growth in capability while being readily integrated into their host platforms. Active phased arrays afford significant radar performance capability while “tile” construct implementations yield minimum volume and weight systems, and effective air-cooling promotes reliable operation.
Phased arrays are configured from a plurality of individual radiating elements whose phase and amplitude states can be electronically controlled. The radiated energy from the collection of elements combines constructively (focused) so as to form a beam. The angular position of the beam is electronically redirected by controlling the elements' phases. The shape of the beam is altered by controlling both the elements' phases and amplitudes. Active phased array antennas include the initial low noise amplifier for receive and the final power amplifier for transmit with each individual radiator, in addition to the phase and amplitude control circuitry. These components are packaged into Transmit/Receive (T/R) modules and are distributed, with the radiating elements, over the array structure.
Tile array implementations package the phased array active circuits into low-profile modules which are disposed in a plane parallel to the radiating face of the array. This is in contrast to “brick” constructs which package the circuitry into higher profile modules which are disposed orthogonal to the face of the array. Tile construction yields relatively thin and hence low volume active phased arrays which are more readily adapted to the host platforms. The construction also results in minimizing weight, which is universally beneficial for all platforms.